Translating device



Oct. 20l 1925.

' G. S. VERNAM TRANSLATING DEVICE Filed April 2l, 1920 4 SheetS-Sht l INVENTOR EQ iff/Wwf@ SfD/SL ATTORNEY Oct.v 20, 1925. 1,557,633

G. S. VERNAM TRANSLATING DEVICE Filed April 21, 1920 4 Sheets-Sheet 2 ATTORNEY Oct. 20, 1925.

G. S. VERNAM TRANSLATING DEVICE 4 Sheets-Sheet 5 Filed A 41 pril 21, 19j@ INVENTOR my I m A Vern/mz PERFORA TOR //O ATTORNEY Filed April 2l, 1920 4 Sheets-Sheet 4 INVENTOR BY/A Var/2am Patented Oct. 20, 1925.

UNITED STATES GILBERT B. VERNAI, OF BROOKLYN, NEW YORK, ASSIGNOR TO AIEBICAN TELEPHONE 1,557,533 PATENT OFFICE.

`AN'D TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

TBANSLATING DEVICE- ammuuon-mea april 21, '1920. serai No. 375,602.

To all whom it may concern:

Be it known that I, GILBERT S. VERNAM, residing at Brooklyn, in the county of Kings and State of New York, have invented certain Improvements in Translating Devices, of which the following is a specification.

This invention relates to transmission systems over which messages are transmitted by code impulses and relates more particularly to a method of and means for automatically translatin portion o the system, such as a land telegraph line, into a code more adaptable for use over another portion of the system, such as a submarine cable.

In the usual type of machine or printing telegraph system the messages or characters may in practice be transmitted thereover by means of the well known Baudot or five unit code, in which each character is represented by a combination of'ive -marking or spacing impulses, which may comprise a combi nation of five sitive or negative impulses if desired. I. en messages or characters are transmitted over a submarine cable, however, the transmission characteristics of the cable, which differ from those of thn telegraph line, make it undesirable to utilize the usual'fve unit printer code and accordingly aspecial cable code is rovided whichis more adaptable lfor use wit the submarine cable. One of the codes which has been found readily adaptable for submarine cable work is a three unit code comprising sitive and negative impulses and interva s of no current at all. As in many instances long submarine cables are worked in conjunction with considerable len hs of land line, it is desirable to have at t e cable stations machinery for transposin the messages automatically from one c e into the other, particularly from the five-un't into the three-unit code. It is a cardinal eature of this invention to provide im roved ar-- rangements for accomplishing t is result. Other features and objects of the invention will appear more fully from the following l detailed description of the invention.l

The invention may be more fully understood from reference to the accompanying drawing in theV Figures 1, 2, 3 and 4 of which are illustrated' arrangements embodying the invention. Fig. 1 illustrates scheu matically the arrangements of the invention as utilized at a. station interconnecting a a code suitable for use over .one

land telegraph line with a submarine cable. In Fig. 2 are shown in detail the arrangements for transposing from the telegraph code into the cable code, while in 3 there is illustrated arrangements in detail v :for transppsing incoming cable messages will o erate a machine perforator of a print ing te egraph set, which will perforate the message characters in code on a tape. This tape will be run through a tape transmitter which operates in conjunction with a plurality of translator relays and the sending'ace of a' distributor and transposes the five-unit code impulses into three-unit code impulses suitable for transmission out over the cable line. The details of the above arrangement are shown in Fig. 2. The messages or code impulses coming in over the cable, which are in the three-unit code, will be amplilied if desired and received on a well known type of cable relay and then transmitted to the re-Y ceivin face of a distributor whiclioperates in conjunction with a plurality of translator relays to transpose the three-unit code impulses into five-unit code impulses. These tive-unit code impulses may operate a printer if desired, or may be utilized to operate a machine perforator which will perforate the code impulses on a message tape. This mesillustrated in the comparative tables of Fig.

The

L The lefbhandv column shows the 32 signal combinations ofthe five-unit code. The shaded areas indicate intervals or -l- (positive) current, while the spaces between them indicate intervals of either 0 or (negative) current. The shaded areas also correspond to the holes in the tape which operate the contacts in the tape transmitter in-- dicated by the :numbersl at the top, e.; irst signai would operate tape transmitter contacts l, and et; the second signal would operate contacts 3 and d, etc. The right-- the hand column shows the signal combinations i for the three-unit code. n the three-unit code there are only 27 signal combinations and accordingly the last 6 signals in the fiveunit code are represented in the three-unit 00de by two successive signals, the first of these in each case being the all negative signal the second being the signal for e corres onding five-unit code signal with the fifth impulse omitted; i. e. the second three-unit signals for signals 27, 28, and 29 are the same as the three-unit si nals for signals 1, 2, and- 3; also the secon signals for 30, 31, and 32 are the same as those for 10, 11, and 12.

A certain relationship exists between the two codes, which relatlonship for the first 18 signals in each code is as follows:

5-unit code 3unit code transmitter contacts operated. polarity of impulse. A B C 1 2 -The above relations hold good for all signal combinations except those operating contacts 1 and 2 together or 4 and 5 together. For all these signal combinations, the middle or B impulse in the threeunit code is ne ative.

ignals 19 to 26 inclusive will operate transmitter contacts 1 and 2. For these signals the relations between the two codes ale as follows: i

. v IS-nnlt code 3-uuit code transmitter contacts operated. polarity of impulse. Signals A B C 19---- 1 2 4 20---- 1 2 21 1 2 5 22----1234 23 1 2 3 -l- 24 1 2 3 5 25 1 2 3 4 5 26 1 2 4 5 The remaining.signals,27 to 32 inclusive,

all operate both contacts 4 and 5 but fail to operate either contact 1 or contact 2. These signals causeythe apparatus to transmit the pointed out to define more clearly Vwhat is meant b the above terms. In the five-unit code, eac signal combination consists of five units, these units vbeing chosen from current impulses such as either marking or spacin impulses and intervals of no current at al In a three-unit code, each signal combination (reference here being had to the reat majorit thereof, such as the first 26 is compo of only three units, these unit-s being chosen from current impulses such as either marking or spacing im ulses and intervals of no current at all. ccordingly, in each of the above codes or systems the unit may be either a current impulse of varied character or an interval of no current at all, the one code having si al combination with five of such units a lece and the other code having signal com inations with three of such units apiece. The invention mayv be more fully understood from the following description of the operation of transposing the messages comin in over the telegraph line in five-unit co e into the three-unit code suitable for transmission out over the cable, reference being had to Fig. 2 of the drawing. vThe cable C is balanced by an artificial line or network Nc-'and is shown connected in the usual duplex manner with a receiving circuit 12, which'will be described later, and with a transmitting circuit. The transmitlting circuit is completed through battery 11 by either one of the relays or pole changers 9 and 10 in such a manner that if relay 9 operates a impulse will. be transmitted over the cable; if relay 10 operates a impulse will be transmitted; and if neither 1rea operates the cable circuit willbeconnectto ground. The relays or pole changers 9 and 10 are operated by im ulses from the segments 6 and 7 of the istributor controlled 'by the translating rela 5^, 4^, 3^, 2^, 1^, and 5B, 4B, 3B, 2g, 1B. ese translating relays in turn are controlled by circuits through the contacts of the tape transmitter 13, which is operated by a tape perforated by signal combinations coming in over the telegraph line in the five-unit code. Inthe drawing the distributor face is shown with the segments 6 and 7 in a straight line, but it is understood that they would normally be arranged in concentric rings and the brushes 8 would be mounted on a rotatin arm.

en the upper brush of the distributor crosses segment T the following circuit will be completed; from battery connected to upr segment 6, brush of distributor, segment il? conductor 14, winding of relay T', winding of magnet M, conductor 15, contact and armature of relay X, to ground. The closing of this circuit will operate magnet M which willv force all the contacts I1,' 2, 3, 4, 5, of transmitter 13 against the righthand bus-bar and stepfthe tape ahead` one ste When the brush passes olf of segment magnet M will be released and a combination of the contacts 1, 2, 3, 4, 5, will vbe operated corresponding to the holes in the tape. These contacts will moveover to the left hand bus-bar, to which is connected battery, and willclose circuits for operating the correspondingly numbered relays 1A to 5A, setting up the same signal combination on them. It is'pointed out at this time that when the brush crosses segment Y the relay Y will not be operated as both ends of its operating winding are connected to battery. When the brush crosses segment R a cireuitwill be closed over conductor 16 and through the winding of relay R', thereby operating relay R. The operation of relay R will release any of the relays 1B, 2B, 3B, 4B, 5B, .that may have been previously operated, as these relays upon operation are locked up over circuits including the armature and contact of relay R', as will appear later. When the brush crosses se ment D,

. battery will :be connected over con uctor 17 to the armatures of relays 1A to 5A and if any of these relays have been operated by the contacts of transmitter 13, the correspondingly numbered relays in the group 1B to 5B will also be operated by the battery connected to conductor 17. In other words the signal combination originating in transmitter 13 will now be set up'on both groups of relays.

While the upper brush is crossing segments'R and D, the lower brush will be crossing segment-A. This will connect bat` tery to the right-hand armature of relay 5A and cause the pole changers 9 and 10 to transmit 'the first of the corresponding threeunit code impulses as will be described later. While the upper brash crosses segment T, the lower brushy will cross se ment B and connect battery to the left-han armature of relay 2B, thus transmittin the second impulse of the three-unit code signal. While the upper brush crosses se ment Y, the lower brush will cross segment and connect battery to the armature of relay 5B, thus transmittin the third impulse of the threeunit code slgnal. These operations will appear more fully later. The transmitter magnet M and the left-hand group of relays, 1 to 5A, will be released and operated again (thereby setting u" a new signal combination) while these last two impulses ot the three-unit code are being transmitted, but

the signal combination set up on the rigl'it.

hand group of relays, 1B to 5B, will be uw affected as these rela s upon operation are locked up thrcugh t eir right-hand Windu ings and contiMLW and over conductor 18 and contact and Aure of relay R to battery. The above method of connection allows for a certain overlap in operation, i. it

permits the transmitter to be operated and the tape stepped forward to set up the next signal combination before the three-unit signal for the previous character has been com letely transmitted. The polarity of the first or A impulse of the signal combination, in the three-unit code is controlled by the right-hand contacts of relays 1A to 5A. If the relays 4A and 5A are both operated, segment A will be con- 75 nected over conductors 19 and 20 to the negative pole changer 10, thereby operating pole changer 10, and accordingly the A impulse will be negative, as will be the case for sig na-ls 25 to 32 inclusive. If one of either 80 relays 4A or 5A is not operated, as would be the case for signals l to 24 inclusive, segment A will be connected over conductor 24 to the armature of relay 2A and the polarity of the impulse to be transmitted will depend on im ulses 1, 2, and 3 in the live-unit code. Now 1f relays 1A and 2Aare both operated, as would be the case for signals 19 to 24 inclusive, the circuit from segment A will be extended over conductor 21 to the con- 9 tact of relay 3A, and if relay 3A is operated the circuit will be further extended over conductor 25 to conductor 22 and positive pole changer 9, thereby Y operating pole. changer 9 Aand causing a positive impulse u to be transmitted out over the cable. However if the relay 3A is, not operated at this time the cablecircuit will be grounded while the brush is on segment A. If relay 2A is not o erated and relay 1A is 10 operated, as would lie the case for signals 1, 4, 7 10, 13 and 16, then segment A will be connected directly to'conductor 22 and thence to the ositive pole changer 9 and the A impulse wi l be positive. If neither relay 2A nor relay 1A is operated, as would bethe case for signa-ls 2, 5, 8, 11, 14 and 17, the circuit of segment A will be open and accordingly the cable circuit will be grounded while the brush is on segment A. If relay 2A is operated and relay 1A is not operated, as would be the case for sgina-ls 3, 6, 9,. 12, 15 and 18, segment A will be connected over conductor 23 to conductor 20 `and thence the negative pole changer 10 and `accordingly the A impulse will be nega-tive. From the above description it will appear that the vA impulse `will always be transmitted acu cording to the key illustrated in Fig. 4. V The polarity et the second or B im pulse et the signal combination in the three unit cede is controlled by the left-hand c i tacts ci relays 2B, 3B, and X. Relay ""i will he operated only by one'ot the last signets., signals 2i" to 32 inclusive, and i 1ibed later. Thereic-re be disregarded 'fer f 1B, 2B, and 3B are 1, 2, and 3 ot the evident that fcr the "L first 26 signal combinations the polarit of the B impulse in the three-unit code wil depend on im ulses 1, 2, and 3 in the fiveunit code. f relays 1B and 2B both operate, as would be the case for signals 19 to 26 inclusive, segment B will be connected over conductors 26 and 27 to conductor 20 and thence to the negative pole changer 10 and accordingly the B impulse transmittedover the cable will be negative. If either or both of relay 1B and 2B fail to operate, segment B will be connected over conductors 28 and 29, back contact4 ofrelay X, and conductor 30 -to the contact of relay 3B. If relay 3B operates, as would be the case for signals 1 to 9 inclusive, the circuit for segment B will then be extended over conductor 31 to conductor 22 and thence to the positive pole changer 9-and the B impulse Atransmitted over the cable will be positive. However, if the relay 3B does not operate, as would be the case for signals 10 to 18 inclusive, the circuit for segment B will remain open and the cable circuit will be grounded. Accordingly fromthe above description it will apl peur that the B impulse will always be transmitted according to the key illust-rated in Fig. 4.

l The polarity of the third or ,C impulse of the signal combination in the three-unit code is controlled by the left-hand contacts of relays 5B, 43,38, and X. The operation of relay X will be described later and the last six signals, signals 27 to 32 inclusive, can be disregarded for the present. If neither relay' 4B nor relay 5B operates, as would be the case for' signals 4, 5, 6, 13, 14, 15, 2O and 23, the circuit of segment C will be ov en and neither of the vpole changers will o erated and the cable circuit will be groun ed while the brush is on segment C. If relay 4B operates but relay 5B does not operate, as would be the case for signals 1, 2, 3, 10, 11, 12, 19 and 22, then segment C will be connected over conductor 32 to conductor 22 and thence to the posith'e pole changer 9 and the C impulse transmitted over the cable will be positive. On the other hand, if relay 5B operates but relay 48 does not operate, as would be the case for signals 7, 8, 9, 16, 17, 18, 21 and 24, then segment C will be connected 'over conductor'33 to conductor 20 and thence to the negative pole changer l0 and the C vimpulse transmitted over the cable will benegati-ve. In the case of signals 25 and 26 the relays 4B and 5B will both be operated and the circuit for segment C will be extended over conductor 29, back contact of relay X, and conductor 30 to the contact of relay 3B. Accordingly in the case of these two last mentioned signals the polarity of the C ,impulse will depend on relay 3H. If relay 3B operates, as in the case of signal 25, the circuit for segment C will be extended vopen and the cable circuit will be positive. On the other hand, if relay 3B' does not operate, as would be the case for signal 26, the circuit for segment C will be ounded. From the above description it w11 appear that the C impulse in the three-unitcode will always be transmitted according to the key illustratedin Fig. 4.

If any one of the last six signal combinations, such as signals 27 to 32 inclusive, is set up on relays 1^ to 5^ a circuit will be prepared for operating relay X. This circuit may be traced from segment D, over conductor 17, back contacts of either relay 1^ or relay 2^, front contacts of relays4^ and 5^, and over conductor 34 to the operating winding of rela X. Accordingly relay X will operate w en the brush crosses segment D. Relay X will lock itself over the following circuit; from ground, right-hand armature and contact of relay X, locking winding of relay X; conductor 18, armature and contact of relay R', to battery and ground. .The operation of rela X will open the previously traced circuit for the operating magnet M and will prepare a clrcuit over conductor 35 for later operating relay Y. When the brush now crosses segment T the transmitter magnet M will not operate and therefore the same signal combination will remain on the transmitter con'- tacts and relays for two revolutions of the brush arm. During the first` of these revolutions the negative pole changer 10 will be connected to all three segments A, B, and C,.in the following manner; to segment A throu h the front contacts of relays 4^ and 5^ an over conductors 19 and 20; to segment B over conductors 20 and 27, left-hand front contact of relay X, conductors 29 and 28. and thence either through the back contact of relay 2B or else through the back contact of relay 1B and the front contact of relay 2B; to se ent C over conductors 20 and 27, left-hand front contact of relay X, conductor 29 and thence through the front contacts of relays 4B and 5B. Therefore'during the first revolution of the brush the or all negative signal will be transmitted in the three-unit code. e

v `When the upper brush crosses segment Y the relay Y' will be operated over a circuit through its upper winding,over conductor 35, contact and armature ofrelay X, to ground. Relay Y will lock itself through itslower windln' and the operating of relay Y will open at lts lower armature the operating circuit for rela 5^, thus releasing relay 5^. The deenerglzation of relay 5^ will open the previously'traced operating circuit for relay X. When the brush crosses segment R the relay R will be operated and its operation will release the relays 1B, 2B, 3B, 4B, 5B, and X, which relays, as has been pointed out, were 4locked up over the contact and armature of relay R. The deenergization of relay X will restore to normal the previously traced circuit for magnet M, so that when the brush now crosses segment T, the magnet M will operate and will step the tape ahead. On thissrevolution of the brush the relays 5A and 5B will not be operated as the circuit for relay 5A is held open by relay Y. The second of the two signals in the three-unit code for the signal combinations 27 to 32 linclusive Will now be transimitated-according to the key illustrated in Fig. 4. `When the brush now crosses segment T, the relay T will be operated as well as magnet M and the operation of rela-y T will release relay-Y, thus restoring the circuit of relay 5A to normal. This will have no eiect on the signal bein transmitted duringjthis revolutionA but w1 1 restore the circuit to normal `for the next revolution.

From the above descri tion it will be seen that the arrangements o the invention will transposey the live-unit signals coming in over the telegraph line into three-unit signals for-transmission over the cable line 1n accordance with the key illustrated in Fig. 4.

The arrangements of the invention adapted for trans osing the messages coming in over the cable in three-unit code into liveunit code suitable for transmission over the telegraph line are illustrated in detail in Fig. 3. The receiving circuit 12 includes a cable relay 41 and correcting and amplifying arrangements 40. As these arrangements are well known in the art a detailed illustration thereof will be omitted. The cable relay 41 in turn c crates two line relays 42 and 43, relay 42 eing operated by negative impulses and relay 43 being operated by positive (-4-) impulses. The contacts of the line relays are connected over conductors 44 and 45 to two of the solid rings of the receiving distributor face and thence through the revolving brushes to the segments connected to a series of selecting relays d+, a-, b+, b", c'+, c-. It is pointed out that the brushes on the sending face of the distributor illustrated in Fig. 2 will rotate in s nchronism with the brushes on the receiving face of the distributor illustrated in Fig. 3. Any well known arrangement may be utilized to accomplish this purpose. These selecting relays will operate and lock up in the usual manner and 'thus store any` signal combinations received over the cable. Associated with and controlled by these selecting relays is a second set of relays such as relays dir ,m an, bn+3 bn c; cn

of the magnets 51, 52, 53, 54, and 55 of a perforator, or a printer if desired, as will punch magnet itself. vThese relays 1n turn control 'the operation An extra set ot` rings, herein .illustrated as the upper set, is provided or timing certain f of the operations. l/Vhen the brush crosses segment F, the relay F will be operated momentarily and it will release any of the relays, such as a}- to 0-, which may have previously been operated and locked up over the contact of relay F. llll/'lien lthe brush crosses segment K, battery will be momentarily connected over conductor 56 to the lower contacts of all the selecting relays, such as relays ahlto 0'. the signal combination previously set up on said selecting relays to be transferred to the lower group of relays which will loclr themselves to battery over the contact and armature of relay F. When the brush crosses segment S the relay S will'be operated and, as the selecting relays lock up overl the contact of relay all of the selecting relays will be released. The apparatus will then be ready to receive the impulses of 'the next signal while the previousselection is being translated and perforated. This arrangement provides for an overlap in the receiving apparatus as 4well as in the sending apparatus previously described.

The lower contacts ofthe lower grouper relays, such as c1- to o--, arc wired to the selecting magnets 51, 52, 53, 54, and 55, of a machine pcrforator in such a way that whenever a three-unit code combination 'is set up on the relays, the periorator selecting magnets `will set up the corresponding liveunit code signal. This arrangement Will be described in. more detail later. The perforator selecting magnets in a well lincwn manner operate 5selecting lingers (not shown) in the perforator so as to interposc them between `the punches and a. punch hammer operated by a punch magnet. This punch magnet 1s illustrated as 4'( ai l is controlled by' the relay P which operat when the brush crosses segment The r- 1.. J P locks itself and holds closed a circuit 'for the punch magnet fl until the latter has operated and perforated holes in the tape cor-- responding to the selection set up on the selecting magnets. lifi/"lien the punch magnet 4T operates it opens a contact which releases the relay ll and this in turn releases the The signal combination set up on the periorator selecting .magnets however is not rel-eased until the brush crosses segment F.

This will cause lli) The method of transposing the three-unit signals into the five-unit code is as follows. referring to the key illustrated in Fig. 4 it will be seen that the first selecting magnet, magnet 51, must operate whenever the first or A impulse of the three-unit code is positive as would be the case for sigmls 1, 4, 7, 1o, 13, 1G, ee, e3, and e4. Selecting magnet 51 is therefore wired to the armature of relay a+ and will operate whenever this relay operates. If relay a+ does not operate, the circuit of magnet 51 will be extended over conductor 57 to the armature of relay band magnet 51 will therefore operate whenever the second or B impulse is negative, as would be the case for signals 19, 20, 21, 25 and 26.

Selecting magnet 52 is wired to the armature of relay L- and accordingly will operate whenever the first or A impulse of the three-unit code is negative, as would be the case for signals 3, 6, 9, 12, 15, 18, 25 and 26. If the relay adoes not operate, the circuit for. magnet 52 will be extended over conductor 57 to the armature of relay band the magnet will therefore operate also in the case of signals 19, 20, 21, 22, 29 and 24.

Selecting magnet 53 is wired to the armature of relay b+ and will therefore operate in the case of signals 1 to 9 inclusive. The circuit'for magnet 5o also may be extended over conductor 58 to the lower armature of relay a"{ and thence over conductor 57 to the armature of relay band accordingly magnet 53 will operate for signals 22, 23, and 24 in which the first or A im ulse is positive and the second or B impu se is negative. Selecting magnet 53 will also operate in the case of signal 25 over a circuit through the back contact of relay b-|, conductor 58, back contact of relay a"+, conductor 59, front contacts of relays c+ and b, and over conductor 60 to the front contact of relay a.

Selecting magnet 54 is wired to the armature of relay c and therefore operates on signals in which the third or C Impulse is positive, as Would be the case for signals 1, 2, 3, 10, 11, 12, 19, 22 and 25. 'In order to cause magnet 54 to operate also in the case of signal 26, its circuit is extended through the back contacts of 'relays c+ and front contact of relay b-, over conductor 60, to front contact of relay a-, to ground.

Selecting magnet 55 is wired through the back contact of rela 48 over conductor 61 to the armature of re a 0-, It will therefore operate on signa s in which the third or C impulse is negative, as would be the case for signals 7, 8, 9, 16, 17, 18, 2l and 24. It will also operate in the case of signals 25 and'26 over a circuit which may be traced through the back contact of relay 0-, front contact of relay b-, conductor 60, front contact of relay a-, to ground.

The last six signals, 27 to 32 inclusive, in which the first three-unit signal is the all negative, or signal will now be considered. The operating circuit for the relay 46 is traced as follows; from ground and battery, winding of relay 46, conductor 62, front contacts of relay 0- and 6-, over conductor 60, front contact of relay a.-, to ground. Accordingly it will be seen that the relay 46 will be operated whenever the relays a-, 12-, and 6-, are operated by the all negative signal in the three-unit code. The operation of relay 46 opens the operating circuit for relay P and therefore the con'lbination set up on the select-ing magnets will not be perforated. lVhen the b rush crosses segment P however a circuit will be completed over conductor 63, winding of relay 48, conductor 64, contact of magnet 47 to ground, thereby operating relay 48, which will become locked up over its left-hand contact and armature to battery. The operation of relay 48 will in turn operate the selecting magnet 55. This causes a fifth impulse to be added to the next combination set up on the selecting magnets. The next revolution of the brushes will set up on the relays a combination which ordinarily correspondsto signals 1, 2, 3, 10, 11, or 12, but due to the fifth impulse added there will now be set up on the selecting magnets the proper one of the last six signal combinations, such as signals 27 to 32 inclusive. Relay 46 will be released when the or all negative signal clears out and relay 48 will be released upon the subsequent operation of punch magnet 47. The circuit will then be restored to its normal condition.

From the above description it will appear that all of the signal combinations coming in over the cable in three-unit code will be transposed by the arrangements of the invention into signal combinations in the fiveunit code in accordance with the key illustrated in Fig. 4.

While a certain arbitrary key, as illustrated in Fig. 4, has been utilized and while the arrangements of the invention have been disclosed in certain specific arrangements which are deemed desirable, it is understood that other keys may be utilized and also that the invention is capable of embodiment in many and widely varied forms other than those specifically disclosed without departing from the spirit of the invention as defined in the appended claims.

What is claimed is:

1. A transmission line, transmitting apparatus associated therewith adapted to transmit three-impulse combinations thereover in accordance with a three-unit code, a transmitter operated in accordance with fiveimpulse combinations of a message trans- VVwetness mitted in a ive-unit code, a series of relays controlled by said transmitter, a second series 'of relays controlled by said first series of relays, locking circuits for said second series of. relays, means controlled by Said first series of relays for determining. the character of the first impulse of the threeunit combination to be transmitted by said transmitting apparatus over said line, means operating subsequent to said determination for releasing 'said first series of relays, means controlled by said second series of relays for determining the character of the second and third impulses of said threeunit colnbination, and means operating subsequent to said last mentioned determination for opening said locking circuits.

2. A transmission line, receiving apparatus associated with said line adapted to receive the three-impulse message combina# tions coming in thereover, said `receiving apparatus including a plurality of selecting relays upon which an incoming threeimpulse message combination may be set up, a recording device upon which may be setup {ive-impulse message combinations, and circuit arrangements completed over the contacts of said selecting relays for controlling said recording device..

3. A transmission line, receiving apparatus associated with said line adapted to receive the three-impulse message combinations coming in thereover, said receiving apparatus including a series of selecting relays upon which an incoming three-im- 35 a recording device upon which may be set 40 up five-impulse message combinations, and circuit arrangements completed over the contacts of said second series of relays for controlling said recordin device.

4. A transmission line, transmitting apparatus associated therewith adapted to transmit three-impulse message combinations tliereover, a transmitter operated in accordance with five-impulse message combinations, a plurality ofl relays controlled by said transmitter for controlling the 0peration of said transmitting apparatus, receiving apparatus associated with said transmission line and adapted to receive the threeimpulse message combinations coming in thereover, said receiving apparatus including a plurality of relays upon which said three-impulse message combinations may be set up, a recording device upon which may be set up five-impulsemessage combinations, and circuit arrangements completed over the contacts of said last mentioned relays for operating said recording device.

In testimony whereof, I have signed my name to this specification this 19th day of 35 April 1920.

GILBERT S. VERNAM. 

